A world I am developing requires that only approximately one quadrasphere or quadrant (1/2 a hemisphere) of the planet be occupied.
I would like the north and south extremes to be outside anything resembling human comfort—far hotter or colder than the daytime Sahara or nighttime South Pole, for instance. There is therefore a single temperate zone, centered somewhere between the pole and the equator, only half of which (divided longitudinally) is habitable.
I don’t have strong opinions about why you can’t go east or west, but it’s a very real barrier, not a misconception or the like.
Total area should ideally be somewhat larger than a quadrant of Earth, but this is a very minor factor if it’s a problem.
Much of the center of the quadrant is taken up by a great sea, such that the large inhabited landmasses extend from the sea out toward the “edge.”
My first thought was to do this with axial tilt, eccentric orbits, things like that. But I realized I simply don’t know nearly enough about such topics as climate science, planetary physics, and so on.
To boil it down:
Is the quadrasphere or quadrant as proposed here possible?
Assuming it is possible, and there is a maximally probable scenario, how would it work?
Insofar as one can predict, what would the various regions outside the quadrasphere or quadrant be like?
NOTE: If there are too many variables here to narrow in on, please itemize these in comments so that I can refine the question.